#include <iostream>
using namespace std;

class A
{
private:
	A()
	{}

public:
	void Func()
	{
		cout << "hello world" << endl;
	}

	static A* GetInstance()
	{
		if (ins == nullptr)
		{
			ins = new A;
		}
		return ins;
	}

private:
	static A* ins;
};
A* A::ins = nullptr;

int main()
{
	
	return 0;
}